The present invention relates to a surgical method and tool for repairing a natural patella of the knee joint and, more particularly, to a surgical method and tool for reshaping a natural patella and fixing a patella implant to the remaining portion of a natural patella.
Joint replacement is becoming increasingly widespread. One of the most widely practiced joint replacement involves the knee joint. In many cases, the replacement of the knee joint with a prosthesis also involves the replacement of a portion of the patella with a prosthetic.
Partial replacement of the patella is widely used in the surgical replacement of a damaged portion of the knee joint. However, it is known that, in a significant percentage of the cases, the patella implant typically fails after five to fifteen years. One of the typically occurring failures is near or at the periphery of the circular or elliptical patella implant, where the thickness of the patella implant material, typically high molecular weight high density polyethylene (HDPE), is at its smallest. A failing patella could lead to significant pain in the patient and typically requires a second operation to replace the failed patella implant and often the entire prosthetic joint.
U.S. patent application Ser. No. 08/375,085 discloses a prosthetic patella implant adapted to structurally fit a remaining portion of the natural patella with maximal preserving of healthy natural tissue and minimal wear of the implant.
U.S. patent application Ser. No. 08/375,927 discloses a surgical method and tool for preparing a natural patella by removing a portion thereof to accept the patella implant described in U.S. patent application Ser. No. 08/375,085.
The present invention further relates to a surgical method and device for preparing a natural patella to accept a patella implant while preserving a predetermined thickness of the natural patella.